The CCR-Flow Core is an indispensable resource for NCI and contractor investigators at the Fredereick National Lab for Cancer research. Seventy six investigators from 37 different laboratories have used the expertise of the flow core staff and the instrumentation available and maintained by the staff. The Flow Cytometry Core staff and instrumentation have supported the following studies: sorting support for adaptive immunity of commensals using RAG transgenic mice with a tdtomato fluorescent protein, the role of MDSC's and regulatory T cells in anti-CD40 tumor therapy, the regulation of erythropoiesis of hematopoitec stem cells by Id2 and the zinc finger protein Pogz; demonstrating the attenuation of immune colitis in mice with an oral delivery of IL-27 recombinant bacteria; showing that in vitro generated Th17 cells can support the expansion and phenotypic stability of CD4+Foxp3+ regulatory T cells in vivo; studies of suppressive oligodeoxynucleotides that reduce lung cancer susceptibility in mice with silicosis; studies of how IFN-gamma causes aplastic anemia by altering hematopoiesis stem/progenitor cell composition and disrupting lineage differentiation; several studies on different aspects of T regulatory cells and several studies on different aspects of the KIR family of proteins. The instruments are used daily by the trained investigators often into the night and on the weekends. The flow core has been training investigators outside of the CIP to analyze their own samples expanding the base of user/operators.This leaves more time for the flow core staff to sort approximately 371 samples and analyze about 7426 samples in the first three quarters of this year. Without the investigators acquiring the data and analyzing their own samples, the government would have to hire full time experienced individuals to perform the same volume of work. At least 15 papers have been published, 1 paper is in press and 14 papers have been submitted in the past year using data obtained in the flow core. The future goals include keeping up with cutting-edge technology in the flow lab by continuing to expand the pool of investigators trained to run and analyze their own samples to all of CCR in Frederick thereby expanding the use, productivity and quality of the science generated using the core's instrumentation and expertise. We have approval to up-grade all of the instruments so that laser and fluorochrome capabilities are more interchangeable giving investigators the flexability to use more than one instrument. This would prevent loss of data because the instrument needed was in use by another investigator or down because of needed repairs. The cell sorters will also be up-graded to allow direct translation of an experiment developed on an analyzer to the cell sorter to sort out the populations of cells of interest to be further studied. It is critical to have this flexability in analysis of samples as well as for sorting of cells. We would also like to stay a cutting edge facility which would require at least one analyzer to be up-graded to analyze at least 28 parameters at once.